Showing papers by "Yu Huang published in 2004"
TL;DR: Nanoscale light-emitting diodes with colors spanning from the ultraviolet to near-infrared region of the electromagnetic spectrum were prepared using a solution-based approach, which could enable a range of integrated sensor/detection "chips" with multiplexed analysis capabilities.
Abstract: Nanoscale light-emitting diodes (nanoLEDs) with colors spanning from the ultraviolet to near-infrared region of the electromagnetic spectrum were prepared using a solution-based approach in which emissive electron-doped semiconductor nanowires were assembled with nonemissive hole-doped silicon nanowires in a crossed nanowire architecture. Single- and multicolor nanoLED devices and arrays were made with colors specified in a predictable way by the bandgaps of the III-V and II-VI nanowire building blocks. The approach was extended to combine nanoscale electronic and photonic devices into integrated structures, where a nanoscale transistor was used to switch the nanoLED on and off. In addition, this approach was generalized to hybrid devices consisting of nanowire emitters assembled on lithographically patterned planar silicon structures, which could provide a route for integrating photonic devices with conventional silicon microelectronics. Lastly, nanoLEDs were used to optically excite emissive molecules and nanoclusters, and hence could enable a range of integrated sensor/detection "chips" with multiplexed analysis capabilities.
675 citations
TL;DR: It is suggested that visceral periadventitial adipose tissue controls mesenteric arterial tone by inducing vasorelaxation via Kv channel activation in vascular smooth muscle cells.
Abstract: Periadventitial adipose tissue produces vasoactive substances that influence vascular contraction. Earlier studies addressed this issue in aorta, a vessel that does not contribute to peripheral vas...
271 citations
TL;DR: In this paper, a general approach for the synthesis of a broad range of semiconductor nanowires (NWs) with precisely controlled chemical composition, physical dimension, and electronic, optical properties using a metal cluster-catalyzed vapor-liquid-solid growth mechanism was introduced.
Abstract: Semiconductor nanowires (NWs) represent an ideal system for investigating low- dimensional physics and are expected to play an important role as both interconnects and functional device elements in nanoscale electronic and optoelectronic devices Here we re- view a series of key advances defining a new paradigm of bottom-up assembling integrated nanosystems using semiconductor NW building blocks We first introduce a general ap- proach for the synthesis of a broad range of semiconductor NWs with precisely controlled chemical composition, physical dimension, and electronic, optical properties using a metal cluster-catalyzed vapor-liquid-solid growth mechanism Subsequently, we describe rational strategies for the hierarchical assembly of NW building blocks into functional devices and complex architectures based on electric field or micro-fluidic flow Next, we discuss a vari- ety of new nanoscale electronic device concepts including crossed NW p-n diode and crossed NW field effect transistors (FETs) Reproducible assembly of these scalable crossed NW de- vice elements enables a catalog of integrated structures, including logic gates and computa- tional circuits Lastly, we describe a wide range of photonic and optoelectronic devices, in- cluding nanoscale light-emitting diodes (nanoLEDs), multicolor LED arrays, integrated nanoLED-nanoFET arrays, single nanowire waveguide, and single nanowire nanolaser The potential application of these nanoscale light sources for chemical and biological analyses is discussed
252 citations
TL;DR: It was concluded that the epimerisation reaction occurring in manufacturing canned and bottled tea drinks would not significantly affect antioxidant activity and bioavailability of total tea polyphenols and most of the observed differences between epicatechins and their corresponding epimers were small, even if they were statistically significant in some cases.
Abstract: Canned and bottled tea drinks contain not only green tea epicatechins (GTE), namely (-)-epigallocatechin gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epicatechin (EC), but also four GTE epimers, namely (-)-gallocatechin gallate (GCG), (-)-catechin gallate (CG), (-)-gallocatechin (GC) and (-)-catechin (C). In the present study we examined the antioxidant activity and bioavailability of these epimers compared with their corresponding precursors. The epimerisation reaction was induced by autoclaving GTE extract derived from longjing green tea at 120 degrees C for 20 min. Isolation and purification of each GTE and epimer were accomplished by various column chromatographic and semi-preparative HPLC techniques. The antioxidant activity of each epimer with its corresponding GTE precursor was conducted in the three in vitro systems, namely human LDL oxidation, ferric reducing-antioxidant power (FRAP), and anti-2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assays. The results of all three assays demonstrated that CG had similar antioxidant activity with its precursor ECG, while GC was less potent as an antioxidant than its precursor EGC. Regarding EGCG and GCG, the antioxidant potency was similar for both LDL oxidation and DPPH free radical assays, but GCG was statistically less effective than EGCG in the FRAP assay. For EC and C, the latter had less anti-free radical activity in the DPPH assay, but in LDL oxidation and FRAP assays the antioxidant activity was similar. Oral and intravenous dosing of GTE-epimer mixture led to increase in total plasma antioxidant capacity in rats. In general, both epicatechins and epimers had low bioavailability (0.08-0.31) and most of the observed differences between epicatechins and their corresponding epimers were small, even if they were statistically significant in some cases. It was concluded that the epimerisation reaction occurring in manufacturing canned and bottled tea drinks would not significantly affect antioxidant activity and bioavailability of total tea polyphenols.
173 citations
TL;DR: Taken together, TRPC3 channels could be directly phosphorylated by PKG at position T11 and S263, and this phosphorylation abolished the store-operated Ca2+ influx mediated by TR PC3 channels in HEK293 cells.
Abstract: Canonical transient receptor potential (TRPC) channels are Ca2+-permeable nonselective cation channels that are widely expressed in numerous cell types. Seven different members of TRPC channels have been isolated. The activity of these channels is regulated by the filling state of intracellular Ca2+ stores and/or diacylglycerol and/or Ca2+/calmodulin. However, no evidence is available as to whether TRPC channels are regulated by direct phosphorylation on the channels. In the present study, TRPC isoform 3 (TRPC3) gene was overexpressed in HEK293 cells that were stably transfected with protein kinase G (PKG). We found that the overexpressed TRPC3 mediated store-operated Ca2+ influx and that this type of Ca2+ influx was inhibited by cGMP. The inhibitory effect of cGMP was abolished by KT5823 or H8. Point mutations at two consensus PKG phosphorylation sites (T11A and S263Q) of TRPC3 channel markedly reduced the inhibitory effect of cGMP. In addition, TRPC3 proteins were purified from HEK293 cells that were transfected with either wild-type or mutant TRPC3 constructs, and in vitro PKG phosphorylation assay was carried out. It was found that wild-type TRPC3 could be directly phosphorylated by PKG in vitro and that the phosphorylation was abolished in the presence of KT5823. The phosphorylation signal was greatly reduced in mutant protein T11A or S263Q. Taken together, TRPC3 channels could be directly phosphorylated by PKG at position T11 and S263, and this phosphorylation abolished the store-operated Ca2+ influx mediated by TRPC3 channels in HEK293 cells.
162 citations
TL;DR: The study indicates that TRPC homologs are widely expressed in human vessels of all calibers, including medium-sized coronary arteries and cerebral arteries, smaller-sized resistance arteries, and vaso vasora.
Abstract: TRPC channels are a group of Ca(2+)-permeable nonselective cation channels that mediate store-operated and/or agonist-stimulated Ca(2+) influx in a variety of cell types. In this study, we extensively examined the expression patterns of TRPC homologs in human vascular tissues. RT-PCR amplified cDNA fragments of TRPC1 (505 bp), TRPC3 (372 bp), TRPC4 (499 bp), TRPC5 (325 bp), TRPC6 (509 bp), and TRPC7 (187 bp) from RNA isolated from cultured human coronary artery endothelial cells. In situ hybridization yielded strong labeling of TRPC1,3-6 in the endothelial and smooth muscle cells of human coronary and cerebral arteries. TRPC7 labeling was exclusively found in endothelial cells but not in smooth muscle cells. Results from immunohistochemical staining were consistent with those from in situ hybridization. Similar expression patterns of TRPC homologs were also observed in arterioles and vaso vasora. In conclusion, our study indicates that TRPC homologs are widely expressed in human vessels of all calibers, including medium-sized coronary arteries and cerebral arteries, smaller-sized resistance arteries, and vaso vasora. These results suggest a ubiquitous role of TRPC homologs in regulating blood supply to different regions and in controlling arterial blood pressure.
99 citations
15 Nov 2004
TL;DR: The proposed methodology enables seamless reuse of the existing standard ATPG based diagnosis infrastructure with compressed test data and indicates that the diagnostic resolution of devices with embedded compression is comparable with that of devices without embedded compression.
Abstract: In scan test environment, designs with embedded compression techniques can achieve dramatic reduction in test data volume and test application time. However, performing fault diagnosis with the reduced test data becomes a challenge. In this paper, we provide a general methodology based on circuit transformation technique that can be applied for performing fault diagnosis in the context of any compression technique. The proposed methodology enables seamless reuse of the existing standard ATPG based diagnosis infrastructure with compressed test data. Experimental results indicate that the diagnostic resolution of devices with embedded compression is comparable with that of devices without embedded compression.
76 citations
TL;DR: It is suggested that ATP acts through both P2X and P2Y purinoceptors to facilitate flow-induced vasodilatation and that ectonucleotidases prevent this effect by degrading ATP on the endothelial cell surface.
Abstract: ATP can be released from endothelial cells, and this release is increased by intraluminal flow in blood vessels. In the present study, the effect of extracellular ATP (1 μM) on flow-induced vasodil...
47 citations
TL;DR: This study demonstrates that raloxifene acutely relaxes rat cerebral arteries largely via an endothelium-independent mechanism, involving inhibition of Ca2+ influx through L-type Ca2+, channels.
Abstract: Background and Purpose—Because of their mixed estrogen-agonist and estrogen-antagonist properties, selective estrogen receptor modulators (SERMs) are considered promising substitutes for hormone replacement therapy. Raloxifene and other SERMs confer estrogen-like cardiovascular protective effects but lack the carcinogenic activity of exogenous estrogen. However, little is known about the cerebrovascular action of raloxifene. Therefore, we studied the effects of raloxifene on the mechanisms regulating rat cerebral artery tone. Methods and Results—Ring segments of the isolated rat posterior communicating cerebral arteries were mounted in a microvessel myograph for measurement of isometric tension. Whole-cell L-type voltage-sensitive Ca 2 currents were recorded using the perforated patch-clamp technique. Raloxifene (0.1 to 10 mol/L) reduced the contractile responses to U46619, phenylephrine, and endothelin-1 in normal Krebs solution or to CaCl2 in Ca 2 -free, high K-containing solution. Raloxifene-induced relaxation was identical in endothelium-intact and endothelium-denuded rings. ICI 182780 had no effect on raloxifene-induced relaxation. Raloxifene reduced L-type Ca 2 currents with a pD2 of 5.980.06, close to that (6.440.09) for raloxifene-induced relaxation of 60 mmol/L K-contracted rings. Conclusions—This study demonstrates that raloxifene acutely relaxes rat cerebral arteries largely via an endotheliumindependent mechanism, involving inhibition of Ca 2 influx through L-type Ca 2 channels. (Stroke. 2004;35:1709
45 citations
TL;DR: The present findings suggest that the COMT and ALDH3 combination may be the most common type involved in predisposing to schizophrenia and blocks the whole pathways for the breakdown of DA and noradrenaline.
Abstract: Schizophrenia is a common mental disorder with a complex pattern of inheritance. Despite a large number of studies in the past decades, its molecular etiology remains unknown. In this study, we proposed a 'system-thinking' strategy in seeking the combined effect of susceptibility genes for a complex disorder by using paranoid schizophrenia as an example. We genotyped 85 reported single-nucleotide polymorphisms (SNPs) present in 23 genes for the dopamine (DA) metabolism pathway among 83 paranoid schizophrenics and 108 normal controls with detailed clinical and genetic information. We developed two novel multilocus approaches-the potential effective SNP combination pattern and potential effective dynamic effects analysis, by which three susceptibility genotype combinations were found to be associated with schizophrenia. These results were also validated in a family-based cohort consisting of 95 family trios of paranoid schizophrenia. The present findings suggest that the COMT and ALDH3 combination may be the most common type involved in predisposing to schizophrenia. Since the combination blocks the whole pathways for the breakdown of DA and noradrenaline, it is very likely to play a central role in developing paranoid schizophrenia.
41 citations
TL;DR: Ovariectomy differentially enhances agonist-induced cerebrovascular tone, an effect that was reversed by estrogen therapy, and tamoxifen may confer beneficial effects similar to estrogen in cerebroVascular vessels.
Abstract: Postmenopausal estrogen deficiency increases the incidence of cerebrovascular disease. However, hormone replacement therapy is associated with an increased cardiovascular risk. Tamoxifen is a selective estrogen receptor modulator with estrogenic effects on cardiovascular risk factors, but its long-term impacts on cerebral vasculature are unknown. We hypothesized that chronic 17beta-estradiol or tamoxifen treatment exerted similar effects in reducing cerebrovascular tension in ovariectomized rats. We therefore determine whether (1) chronic 17beta-estradiol treatment could influence vasomotor activities, (2) chronic tamoxifen therapy could exert an estrogen-like or estrogen-antagonistic effect, and (3) acute exposure to estrogen could mimic the effect of 17beta-estradiol. Isometric tension was measured in cerebral arteries from female rat groups: control, ovariectomy, ovariectomy plus 17beta-estradiol treatment, ovariectomy plus tamoxifen treatment, and ovariectomized rats treated with tamoxifen and 17beta-estradiol. Ovariectomy enhanced cerebrovascular contractions to endothelin-1 or CaCl2, but not to U46619 or phenylephrine. 17beta-Estradiol therapy reversed these effects. Chronic tamoxifen treatment exerted estrogen-like actions by reversing ovariectomy-induced enhancement of vessel tone without antagonizing the effect of chronic 17beta-estradiol treatment. Ovariectomy enhanced the relaxing potency of nicardipine, and 17beta-estradiol treatment prevented this effect. Acute exposure to 10(-9) mol/L 17beta-estradiol or 10(-8) mol/L tamoxifen did not modulate contractions in rings from nonoperated female rats. In conclusion, ovariectomy differentially enhances agonist-induced cerebrovascular tone, an effect that was reversed by estrogen therapy. Tamoxifen does not act as an estrogen antagonist; instead, it functions as an estrogen agonist during estrogen deficiency. Thus, tamoxifen may confer beneficial effects similar to estrogen in cerebrovascular vessels.
TL;DR: Based on synthetic analysis of the characteristics of the ecology and environments of China, the principles of ecological regionalization are discussed, and indices and nomenclature of ecological regionization are proposed as mentioned in this paper.
Abstract: Ecological regionalization is a base for rational management and sustainable utilization of ecosystems and natural resources. It can provide a scientific basis for constructing healthy ecological environments and making policies of environmental management. In this paper, based on synthetic analysis of the characteristics of the ecology and environments of China, the principles of ecological regionalization are discussed, and indices and nomenclature of ecological regionalization are proposed. The ecoregions on a national scale are divided. The results show that there are 3 domains, 13 ecoregions and 57 ecodistricts. The present scheme can be used as a framework for ecosystem assessment and management. Based on the ecoregions, measurements of management for forest, grassland, agriculture and wetland ecosystems are recommended. The experience and information can be used within and beyond the national scale for land-use planning, biodiversity conservation and ecosystem restoration.
TL;DR: Data suggest that baicalein potentiates Ca2+-mediated Cl– secretion through a signaling pathway involving cAMP and protein kinase A, most likely through the cystic fibrosis transmembrane conductance regulator in the apical membrane.
16 Feb 2004
TL;DR: The experimental results presented demonstrate that the proposed diagnosis algorithm is effective for large industrial designs with multiple intermittent scan chain faults.
Abstract: A new algorithm to diagnose intermittent scan chain fault in scan-based designs is proposed in this paper. An intermittent scan chain fault sometimes is triggered and sometimes is not triggered during scan chain shifting, which makes it very difficult to locate the fault sites. In this paper, we provide answers to three questions: (1) Why intermittent scan chain faults happen? (2) Why diagnosis of this type of faults is necessary? (3) How to diagnose this type of faults? The experimental results presented demonstrate that the proposed diagnosis algorithm is effective for large industrial designs with multiple intermittent scan chain faults.
TL;DR: The dried roots of Scutellaria baicalensis Georgi (Huangqin) are widely used in traditional Chinese medicine and two flavonoids, baicalin and baicalein, were purified from the dried roots and examined their effects on isolated rat aortic rings.
TL;DR: All theaflavins and catechins were more powerful than BHT as an antioxidant in heated canola oil.
Abstract: The present study examined the antioxidant activity of black tea theaflavins and catechin derivatives in canola oil. Oxidation was conducted at 95°C by monitoring the oxygen consumption and decreases in the linoleic and α-linolenic acids of canola oil. All were tested at a concentration of 0.5 mM. Catechins, including (−)-epicatechin, (−)-epicatechin gallate, (−)-epigallocatechin, and (−)-epigallocatechin gallate (EGCG), were more effective than theaflavins, namely, theaflavin-1, theaflavin-3-gallate, theaflavin-3′-gallate, and theaflavin-3,3′-digallate (TF3), against the lipid oxidation of canola oil. Among the four theaflavins, TF3 was the most effective, whereas among the four catechins, FGCG was the most potent. Under the same conditions, all theaflavins and catechins were more powerful than BHT as an antioxidant in heated canola.oil. Little or no difference in antioxidant activity was observed between each catechin and epimer pair. Methylation of the 3′-OH led to a significant loss of antioxidant activity of the catechins.
TL;DR: In this article, the authors have developed a new ceramics forming process, colloidal injection molding, with the potential of forming large ceramic parts of complex shapes such as engine turbines and biomedical implants.
TL;DR: Both NO and EDHF are involved in the regulation of the vascular tone in the coronary arterial and venous systems but the amount of NO release and the EDHF-mediated relaxation and associated hyperpolarization are less significant in the vein than in the artery in theocardial system.
Abstract: OBJECTIVE We compared the basal and bradykinin (BK)-induced NO release and endothelium-derived hyperpolarizing factor-mediated function between coronary arteries and cardiac veins. METHODS AND RESULTS Isolated coronary vessels (large arteries, cardiac veins as well as microvessels) were studied. An NO-specific electrode and a conventional intracellular glass microelectrode were used to directly measure NO released from endothelial cells and hyperpolarization of smooth muscle cells in conduit coronary vessels. The basal and BK-induced release of NO was 14.2 +/- 2.0 nmol/L and 237.1 +/- 27.2 nmol/L (n = 8) in the artery, significantly greater than in veins (8.0 +/- 1.1 nmol/L and 135.6 +/- 14.5 nmol/L, n = 8, P < 0.01). The BK-induced hyperpolarization was significantly reduced by N-nitro-L-arginine, indomethacin, and hemoglobin in both arteries and veins and was greater in the arteries. The EDHF-mediated relaxation was significantly higher in the arteries than in veins, greater in microveins than in large veins, and almost abolished by charybdotoxin and apamin. CONCLUSIONS Both NO and EDHF are involved in the regulation of the vascular tone in the coronary arterial and venous systems but the amount of NO release and the EDHF-mediated relaxation and associated hyperpolarization are less significant in the vein than in the artery in the coronary system.
Journal Article•
TL;DR: This review highlights the current novel findings on the molecular and cellular mechanisms by which urocortin may exert its cardiovascular protective action.
Abstract: Urocortin and other hypothalamus corticotropin-releasing factor (CRF) polypeptides play biologically diverse roles in the stress, cardiovascular and inflammatory responses by acting on central and peripheral CRF receptors. Urocortin shows a significantly high sequence homology to CRF, and the concurrent expression of type-2 CRF (CRF2) receptors with urocortin in the heart suggests that urocortin may play a physiological role in the cardiac function. Urocortin is thought to be the endogenous agonist producing the cardiovascular actions previously attributed to CRF. This review highlights the current novel findings on the molecular and cellular mechanisms by which urocortin may exert its cardiovascular protective action.
TL;DR: Investigation of the role of endothelial [Ca2+]i, nitric oxide (NO), and cyclic GMP in acteoside-induced inhibition of endothelium-intact rings impairs endothelial NO-mediated aortic relaxation partially through inhibition of agonist-induced endothelial Ca2+ mobilization and Ca2-dependent NO production and subsequent suppression of cyclicGMP formation.
01 Oct 2004
TL;DR: In this article, the in-situ study of steel corrosion in sea bottom sediment (SBS) was carried out by Transplanting Burying Plate method (TBP method).
Abstract: The in-situ study of steel corrosion in sea bottom sediment (SBS) was carried out by Transplanting Burying Plate method (TBP method). It was found that the corrosion rate of steel in the sea bottom sediment with sulfate reducing bacteria (SRB) could be as high as ten times of that in sea bottom sediment without SRB. The experiments in simulated sea bottom sediments with different SRB contents by artificial culturing showed that the electrochemical behavior of steel in the sea bottom sediment with SRB was different from that without SRB. SRB altered the polarization behavior of steel significantly. The environment was acidified due to the activity of SRB and the corrosion of steel was accelerated. The corrosion of carbon steel in sea bottom sediment is anaerobic corrosion, and the main factor is anaerobe. There are SRB commonly in SBS, and the amount of SRB decreases along with the depth of sediment. Because of the asymmetry and variation of sea bottom sediment, the most dangerous corrosion breakage of steel in SBS is local corrosion caused by SRB. So the main countermeasure of corrosion protection of sea bottom steel facilities should be controlling of the corrosion caused by anaerobe.
TL;DR: In this paper, the forward mode of Na(+)-Ca(2+) exchangers play a role in the relaxant responses to urocortin in isolated rat small pulmonary arteries.
TL;DR: Urocortin relaxed rat pulmonary arteries via CRF receptor-mediated and PKA-dependent but endothelium/NO or voltage-gated Ca2+ channel-independent mechanisms and partly via inhibition of a PKC-dependent contractile mechanism.